DESCRIPTION: (Applicant's Abstract) In spite of the negative health effects of cigarette smoking, if current trends continue, smoking rates for women will surpass men by the year 2000. Studies show that women have a greater fear of weight gain after quitting, as well as, they tend to gain more weight to suggest gender specific cessation strategies are needed. Animal and clinical studies suggest that estrogen could decrease appetite behavior and minimize weight gain, as well as, affect mood and therefore could attenuate withdrawal symptoms. However, no study has systematically and comprehensively investigated the different effects of estrogen replacement therapy (ERT) in smoking cessation in postmenopause where the estrogen level is low. This renewal application will address this area in a randomized double blind nontreatment study conducted in 2 parts over 4 years. Part I investigates if there is a differential effect of ERT on appetitive behavior and withdrawal symptoms in postmenopausal women during short term smoking cessation, i.e., to decrease appetite behavior and minimize weight gain, and affect mood and attenuate withdrawal symptoms. Eligible subjects are randomized to smoking and non-smoking status, and enter a 3-week period of scheduled measurements. Week 1 is baseline with smoking ad lib, and in weeks 2 and 3 some subjects stop smoking while others continue smoking. During these 3 weeks weight, caloric intake, RMR and tobacco withdrawal symptom measurements will be done. Part II is also a short term nontreatment study investigating the additive effects of ERT on the same parameters in postmenopausal women on nicotine replacement. Subjects are randomized to ERT and placebo and monitored for 1 month, then randomized to placebo or active patch. The study design and measurements are identical to Part I. The results of this research will increase our understanding of the functional relationships between ERT and appetitive behavior and withdrawal symptoms in smoking cessation in postmenopausal women. This research will provide new information which will be important and useful in assessing direction for specific and more effective treatment strategies for smoking cessation in women during the postmenopausal years.